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单选题
The purpose of the low pressure cut-out switch is to （）.
A
maintain liquid refrigerant at the suction of the compressor
B
maintain a preset suction pressure to the compressor
C
start and stop the compressor at preset operating pressures
D
operate at minimum efficiency
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单选题If a firefighting situation calls for low-velocity fog you would（）.A
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单选题The device used for low-pressure control and high-pressure cutout on a compressor is called a（）A
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Trough of low pressureC
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单选题If a refrigeration compressor were short cycling on the low pressure cutout switch, the probable cause for this might be the （）.A
system was overcharged with refrigerantB
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单选题If a refrigeration crankcase compressor were short cycling on the low pressure cutout switch, the cause might be that the （）.A
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单选题If the compressor runs continually, the cause might be the（）A
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cast iron has weaknessB
cast iron can stand up shock loadingC
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above the polar circlesB
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考题
单选题The purpose of the refrigeration system low pressure cutout switch is to （）A
protect the compressor from liquid flood backB
protect the compressor from low discharge pressureC
start and stop the compressor upon system demandD
start the compressor after a drop in the evaporator pressure
考题
单选题The sensing line for the low pressure cutout switch to a refrigeration system is located （）.A
in the chill boxB
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on the discharge side of the compressor
考题
单选题If a compressor runs continuously, the cause might be a（）A
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